BACKGROUND: The purpose of the present study was to conduct a comprehensive evaluation of clinical and metabolic factors in order to determine the characteristics of urolithiasis in a Korean population, compared with other ethnic groups. In addition, clinical and metabolic factors associated with calcium oxalate (CaOx) and uric acid (UA) stone formation were compared. METHODS: A total of 211 Korean patients with urolithiasis were analysed. Biochemical components in 24-hour urine were determined and the relative supersaturation (RSS) was calculated using the EQUIL 3 software program. Physical analysis of stone composition using Fourier Transform-Infrared spectrometry (FT-IR), blood chemistry, and demographics were also investigated. RESULTS: A previous history of urolithiasis and male gender were found to be clinical risk factors related to urolithiasis. Metabolic abnormalities, including hypercalciuria, low urine volume, natriuresis, hypocitraturia, and hyperoxalaturia were commonly found in 24-hour urine. Korean patients had higher calcium, lower citrate, lower phosphate, lower urine volume, and higher RSS with respect to UA than Caucasian patients. Patients with CaOx stone formation (n = 100) were younger and excreted a higher level of calcium and higher UA at a higher pH than patients with UA stones (n = 37). A significant difference in RSS was observed with respect to CaOx, while there was no significant difference in RSS with respect to UA between them. CONCLUSIONS: Metabolic abnormalities, including hypercalciuria, low urine volume, natriuresis, hypocitraturia, and hyperoxalaturia were important findings in Korean patients with urolithiasis. In addition, clinical and metabolic characteristics of CaOx stone formers differed in comparison with UA stone formers.
BACKGROUND: The purpose of the present study was to conduct a comprehensive evaluation of clinical and metabolic factors in order to determine the characteristics of urolithiasis in a Korean population, compared with other ethnic groups. In addition, clinical and metabolic factors associated with calcium oxalate (CaOx) and uric acid (UA) stone formation were compared. METHODS: A total of 211 Korean patients with urolithiasis were analysed. Biochemical components in 24-hour urine were determined and the relative supersaturation (RSS) was calculated using the EQUIL 3 software program. Physical analysis of stone composition using Fourier Transform-Infrared spectrometry (FT-IR), blood chemistry, and demographics were also investigated. RESULTS: A previous history of urolithiasis and male gender were found to be clinical risk factors related to urolithiasis. Metabolic abnormalities, including hypercalciuria, low urine volume, natriuresis, hypocitraturia, and hyperoxalaturia were commonly found in 24-hour urine. Korean patients had higher calcium, lower citrate, lower phosphate, lower urine volume, and higher RSS with respect to UA than Caucasian patients. Patients with CaOx stone formation (n = 100) were younger and excreted a higher level of calcium and higher UA at a higher pH than patients with UA stones (n = 37). A significant difference in RSS was observed with respect to CaOx, while there was no significant difference in RSS with respect to UA between them. CONCLUSIONS:Metabolic abnormalities, including hypercalciuria, low urine volume, natriuresis, hypocitraturia, and hyperoxalaturia were important findings in Korean patients with urolithiasis. In addition, clinical and metabolic characteristics of CaOx stone formers differed in comparison with UA stone formers.